Door closer



E. P. BUGGE DOOR CLOSER March 23, 1965 2 Sheets-Sheet 1 Filed Nov. 6, 1961 24 I INVENTOR. flea/w F 61/666 March 23, 1965 E. P. BUGGE 3,174,177

DOOR CLOSER Filed Nov. 6, 1961 2 Sheets-Sheet 2 INVENTOR. [24 we F3066! United States Patent 3,174,177 DGUR CLOSER Erling P. Bugge, R0. Box 33183, Wilshire-La Brea Station, Los Angeles, Calif. Filed Nov. 6, 1961, er. No. 150,325 2 Claims. (Cl. 1653) The present invention relates generally to door closers and, more particularly, to a door closer incorporating a check to prevent slamming of the door while, at the same time, ef ecting a positive closing of the door.

An object of my invention is to provide a door closer that is fully concealed from View when mounted in operative position and giving evidence of its presence only by its operation.

Another important object of my invention is to provide a door closer mechanism which may also serve as a hinge support for the door and, additionally, is adaptable to use in either single or double acting doors.

Yet another object of the invention is the provision of a door closer having a novel cam means for translating rotation of an actuating shaft into operation of a check device, the cam means inducing positive closing action of the door and also, providing a vastly simplified structure for incorporating either or both of a pair of stop means, first, to limit opening movement of the door and, second, for yieldably holding the door in an open position. Additionally, the cam feature is important in effecting a reduction in the overall size of the door closer and, therefore, the size of the door framing elements, whereby a significant reduction in cost is achieved.

Yet another important objective of the invention is the provision of a door closer with an actuating arm mechanism adapted for concealed mounting in the top rail of the door. Further, the actuating arm mechanism has adjusting means to effect compound movement of the door relative to its frame whereby to insure perfect registration of the door with its frame opening. With this arrangement, a door can be swiftly and precisely mounted in its door frame.

Yet another object of the invention is to provide a novel restrictor valve for a door check mechanism which can be readily adjusted to exercise a fine degree of control over the resistivity of the check.

It is also an object of the invention to provide a door closer of simplified construction so as to achieve a significant reduction in manufacturing costs but, nevertheless, calculated to have a long and efficient service life with a minimum of attention.

These and other objects and advantages of my invention will be apparent from the following description of a presently preferred embodiment, when taken in conjunction with the annexed drawings.

FIGURE 1 is a partial perspective view of a door frame and door, portions of the frame header being cut away to show the mounting of one part of my door closer, the door being lowered away from the header to reveal another part of the door closer in an upper corner of the door.

FIGURE 2 is a vertical sectional view taken longitudinally of the two parts of the door closer shown in FIGURE 1, when the two parts are in operatively interconnected position and the door of FIGURE 1 is mounted in place and in closed position,

FIGURE 3 is a horizontal sectional view taken on the line 3-3 of FIGURE 2, showing parts of the check unit in the positions assumed when the door is closed and, also, showing in phantom outline, the positions of the parts when the door is in full open position.

FIGURE 4 is a partial sectional view of an alternative embodiment of the camming means adapted to provide a hold-open stop.

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FIGURE 5 is a partial sectional view of the adjustable restrictor valve means shown in FIGURE 2.

FIGURE 6 is a partial sectional view taken on the line 66 of FIGURE 5.

FIGURE 7 is a top plan view of the adjustable actuator arm mounted in place on the top rail of the door.

FIGURE 8 is a sectional view on the line 88 of FIGURE 7.

FIGURE 1 shows a portion of a door frame defined, in part, by a header 10 and jamb 11. A portion of the header It is cut away to show the concealed mounting of a sealed, oil filled housing 12 for the door closer and check mechanism of my invention. An actuator arm 13 of my invention is mounted in a top rail 14 of a door 15.

As is obvious, the door frame is defined by the fioor, or a door sill, a pair of the jambs 11 and the header 10. In FIGURE 1, the door 15 has been illustrated in a lowered position in order to reveal, in perspective, the configuration of the actuator arm 13. However, it will be understood that the weight of the door 15 is supported by a hinge pin, or the like, secure in the door sill or the portion of the floor within the door frame, to hingedly hold the door in swinging registration with the door frame opening. The housing 12 is mounted in the header 10 to position the protruding end of an actuator shaft 16 coaxially with the floor or door sill mounted lower hinge pin, the two parts together defining the hinge axis of the door. While the hinge axis is thus illustrated in the embodiment of FIGURE 1 as being spaced from the jamb 11, it will be obvious to those skilled in the art that the hinge axis could also be positioned adjacently to or coincident with the jamb,

While my invention may, of course, be utilized with other door framing materials, it has special advantages in metal framing of the type shown in FIGURE 1. Thus, the header 10 is a box beam whose size is primarily dictated by the size of the door closer unit to be mounted therein. As will appear, my invention achieves a unit of significantly reduced size whereby to permit using box beam headers having a smaller cross-sectional area, which permits a significant saving in the cost of the header. Similarly, the actuator arm 13 has special utility in doors having metal framing elements and is particularly adapted for utilization with the illustrated top rail 14 of the door 15, this top rail being of H or I-beam configuration, having a web section interconnecting opposite flanges to define a channel within which the actuator arm 13 is hidden from view when the door is mounted in place.

The housing 12 is preferably a casting of elongated rectangular configuration and adapted to be received within the header 10 by movement into an open end of the header, before the header is mounted in place on the door jambs. To permit passage of the protruding end of the actuator shaft 16 and of a protruding boss 17 formed in the lower wall of the housing 12, the bottom wall of the header 10 has a portion at one end cut away. After the housing 12 is located in the desired position within the header 10, it is locked against movement by a suitable screw 18 through a bore in the bottom wall of the header 10 that is received in a tapped blind bore provided in a boss 19 formed in the bottom wall of the housing 12. A cover 20 or the like may be secured by screws 21 to a jamb-mounted header support member 22 and the end of the housing 12, whereby to conceal that portion of the housing between the adjacent jamb 11 and the boss 17.

At the end of the housing 12 remote from the actuator shaft 16, the housing is formed with a parallel pair of cylinders 23 that are closed at outer ends by a cover 24 held in place by a suitable bolt 25 and retaining a gasket 26. Each cylinder 23 contains a reciprocable piston 27 connected to one end of a coaxial piston rod 28. Interiorly of the housing 12, and at about the mid portion of the housing, a pair of ribs 29 are provided, each of which is formed with a bore 30, coaxially related to a cylinder 23, to provide plain bearing support for the other end of the one of the piston rods 28. A cam yoke 31 having the ends of its free arms bridged by a bar 32, is secured to the ends of the pair of piston rods 28 protrudi-ng beyond the ribs 29.

To effect closing movement of the door, a pair of coil springs 33 is provided within the housing 12. Each of these springs has a fixed abutment at one end on one face of one of the ribs 29 and is coiled around one of the piston rods 28. At its other end, each coil spring 33 has a seat in an annular groove 34 formed in the rear face of the corresponding piston 27.

As is apparent, the cam yoke 31, bar 32, pair of piston rods 28 and the pistons 27 comprise a unitary assembly normally biased to the full line position shown in FIG- URE 3 by a pair of springs 33. This assembly reciprocates within the confines of the housing 12, opening movement of the door effecting movement of the assembly to the left, as viewed in FEGURE 3, towards the phantom outline position, to compress the springs 33. Upon release of the door, the compressed springs 33 then return the assembly back to the full line position. The housing 12 is filled with oil or the like and bypass means are provided whereby oil displaced by the pistons 27 during opening of the door will not unduly restrict the rate of opening. To prevent slamming of the door upon closing movement, the bypass means are checked and the oil displaced by the pistons 27 upon their return movement is diverted through a restrictor valve means.

The top wall of the housing 12 is formed, at the end opposite the cylinders 23, with a tapped opening 35, sufiiciently large to permit the entrance of the cam yoke 31, the bar 32 and the actuator shaft 16. The opening 35 is counterbored to provide a seat for a suitable sealing gasket 36 and threadedly receives an appropriate cover 37, which when seated is disposed in flush relationship to the outer surface of the top wall of the housing 12.

Within the housing 12, the actuator shaft 16 has its upper end supported in a ball bearing assembly 38 mounted on the inner face of the cover 37, while the protruding or lower end portion of the actuator shaft is similarly supported in a ball bearing assembly 39 mounted in the thickened boss 17 on a seal 40. That portion of the actuator shaft 16 within the housing 12 is integrally formed with a pair of similar cross-arms 41 of generally arcuate configuration, as indicated in FIGURE 3. Referring to FIGURE 2, it will be seen that the cross arms 41 are vertically spaced apart and at their opposite extremities support a pair of cam follower rollers 42 having vertical axes of rotation on a pair of pins 43 secured to and extending between the cross arms. It will also be observed fom FIGURE 2 that the actuator shaft 16 has a coaxial portion 44 in the space between the cross-arms 41 that is of a reduced diameter and yoke 31 has a thickness to permit the web portion thereof being admitted into the vertical space between the cross arms, on that side of the reduced diameter portion 44 disposed oppositely to the bar- 32.

The yoke 31 has a cam edge 45 that is biased into contact with the rollers 42 of the actuator shaft 16 by the springs 33. When the door 15 is swung in either direction to rotate the shaft 16, the cam 45 effects translatory. movement in a corresponding direction of the cam yoke 31, piston rods 28, and pistons 27.

Referring to FIGURE 3, the cam edge 45 has an axis of symmetry 46 coincident with the longitudinal axis of the housing 12 and intersecting a rotational axis 47 of the actuator shaft 16. This rotational axis 47 is offset from a line 48 including the rotational axes of the pair of rollers 42 and, when the door 15 is in closed position so as to dispose the pair of actuator cross arms 41 in the 4 solid outline position of FIGURE 3, the line 48 is disposed normally to the axis of symmetry 46.

In the phantom outline position of FIGURE 3, the actuator shaft 16 has been swung counterclockwise from its solid outline position, as indicated by the directional arrow 49, by corresponding swinging of the door through As will appear, the cam edge 45 is particularly adapted to limit opening movement to 90 but can be adapted, if desired, to permit an arc of movement of More particularly, the cam edge 45 has three symmetrical pairs of curved portions 45a, 45b and 450, each of these having a constant radius of curvature. The portions 45a are adapted to provide a rolling clearance for the pair of rollers 42, when these rollers are swung through that portion of their are most'remote from the axis of symmetry 46. Accordingly, the portions 4521 have a radius of curvature at least as great as the radius of the rollers and have tangents parallel to the axis of symmetry 46, but spaced from the axis of symmetry a distance at least as great as the sum of the roller radius and the distance from the rotational axis 47 to the axis of a roller 42. Thus, when the actuator shaft 16 starts movement from its full line position of FIGURE 3, in the are 49, the upper roller 42 first enters the corresponding enlarged cam portion 450 while the lower roller 42 swings clear of its corresponding cam edge portion 45aand comes into contact with the corresponding cam edge portion 45c. As the upper roller 42 then passes over center of the rotational axis 47, it withdraws from the corresponding cam edge portion 45a and commences to travel on the corresponding cam edge portion 45b.

The two curved portions 45b merge into a straight edged or crest portion 45d, extending normal to the axis of symmetry and having a total length substantially twice the normal distance between the rotational axis 47 and the line 48 that extends between the axes of the pair of rollers. When the actuator shaft 16 has been turned through 90, as indicated in FIGURE 3, to the phantom outline position, the line 48 is disposed parallel to the axis of symmetry 46 and intersects one end of the straight portion 45d. Simultaneously, a roller 42 has been swung into contact with one of a pair of straight edge portions 45a that are parallel to the axis of symmetry, thus providing a; positive stop preventing opening of the door beyond 90.

With this arrangement, both the straight edge portion 45:! and the pair of straight edges 45e serve to limit the degree of opening movement, but neither of these may be employed to the exclusion of the other and yet achieve a limit to door opening. As is apparent, it is desired to increase the permissible range of opening, the space b tween the parallel straight edge portions 45e may be increased, but preferably not beyond a point at which the roller 42 riding on the crest portion 45d would go over center of the axis of symmetry 46. As will be apparent, so long as the axis of the roller 42 riding on the portion 45d is restrained against crossing the axis of symmetry 46, the door will automatically close under the force of the compressed springs 33.

FIGURE 4 shows an alternative form of cam edge 45' for the cam yoke 31, to provide a stop for holding the door in a full open position. The cam edge 45 is similar to the cam edge 45, having identical portions 45a, c and e. The cam edge 45 has a symmetrical pair of curved portions 45b that are similar in configuration to the pair of curved portion 45b of the cam edge 54, but shorter in length. In the alternative cam edge 45, the crest of the cam at 45d is of greater length than the straight edged portion 45:! and, unlike the latter, is not tangent to the extremities of the curved portions 45b. Instead, the crest portion 45d, while being straight for a major portion of its length, has curved extremities adapted to provide detents for seating one or the other of the rollers 42 when the line 48 is disposed parallel, or substantially so, to the axis of symmetry 46. The pair of detents thus provided will yieldably hold the door in open position. As is ap- 3 parent, if the door is open and sufiicient closing pressure is applied to it, the one of the rollers 42 engaged with a detent will override the crest defined at the junction of the end of the portion 45d with the corresponding end of a portion 45b and, thereafter, the door will be free to close under the force of the compressed springs 33.

Obviously, a cam yoke may be devised in which the crest portion is not symmetrical, so as to incorporate onehalf of the straight edged portion d and one-half of the portion 45d, whereby the door 15 can be held open in one direction only. Additionally, if it is desired to have a door than can be held open, in both directions, at an angle of more than 90, but one detent position need be provided in the crest portion, centered on the axis of symmetry 46, along with a corresponding increase in the spacing between the parallel straight edge portions 45c.

If it is desired to have a door that will swing open in one direction only, with or without a hold-open detent, it is, nevertheless, important to utilize the pair of rollers 42 offset from the shaft axis 47, on the line 43, with the symmetrical pairs of cam portions 45a, [2 and c. The offset rollers 42 insure a positive, automatic closing of the door even if the door can be opened beyond 90. Additionally, the fact that there is a substantial sector of the 90, or more, arcuate range of movement of the rollers 42 during which both rollers have simultaneous rolling contact with oppositely disposed cam edge portions, creates positive action during both opening and closing of the door. Thus, at all times during which one of the rollers 42 has contact with its companion cam edge portion 45c, the other roller is traveling on either its edge portion 45a or 4511. During this phase, sudden changes in the rate of opening or closing the door, as by somebody lurching against the door, are dampened because the cam edge, being snugly engaged at opposite points, only permits gradual changes of rate.

In order to provide a bypass for fluid in the housing 12 displaced by the pistons 27 when the door is opened, a parallel pair of passages are formed in the portion of the housing separating the pair of cylinders 23, each having an enlarged downstream end 51 to hold one of a pair of ball checks 52. Each of the passages 5 at its downstream end has communication with a cavity 53 formed in the inner face of the cover 24. Accordingly, when the pistons 27 move to the left from the solid outline positions shown in FIGURE 3, fluid enters the upstream ends of the passages 5t and is admitted into the cavity 53, past the ball checks 52, relatively freely, the passages 59 being sufficiently great in area so as to not unduly restrict the rate of opening of the door 15.

When the door closes, the cause returning movement of the pistons 27 from their phantom outline positions in FIGURE 3, the displaced fluid is prevented from entering passages 54) by the ball checks 52 and is so diverted into a return passage 55, that is also formed in the housing 12, in the area between the pair of cylinders 23. This return passage is intersected by a relatively large diameter blind bore 56, opening into the bottom of the housing 12 and, also, counterbored at its lower end for mounting the restrictor valve means of my invention.

This restrictor comprises a sleeve 57 that is angularly slidable in the blind bore 56 and itself adapted to receive an axially adjustable cylindrical valve member 58. The sleeve 57 is formed with a diametrically opposite pair of radially extending ports 59, of smaller diameter than the return passage 55, and the sleeve at its lower end has a circumferentially extending exterior flange 69 for seating on a shoulder of the blind bore 56, on top of a seal ring 61. The ports 59 are thus positioned at the level of the return passage 55, but can be moved or less into and out of alignment with the return passage, in order to vary the effective cross-sectional area of the ports. This angularly adjustability of the sleeve 57 accordingly gives one range of adjustment to the restrictor valve.

The sleeve 57 is held in place in the blind bore 56 by a tubular nut 63 engageable with an enlarged diameter, tapped, counterbore portion, in the lower end of the blind bore 56. The nut 63 is itself tapped to receive a threaded portion 64 of the valve member 58 whereby the valve member is axially adjustable within the sleeve 57. Referring to FIGURE 5, it will be apparent that raising and lowering of the valve member 58 accomplishes a second degree of control over the elfective cross-sectional area of the restrictor valve, by raising and lowering the upper end of the valve member relative to the radial port 59 of the sleeve. To prevent leakage of fluid along the stem of the valve member 58, the sleeve 57 is counterbored to provide a seat 65 for an O-ring 66. As shownin FIGURE 2, a hole 67 is formed in the bottom wall of the header 1% in registration with the restrictor valve to permit adjustment of both the sleeve 57 and valve member 58, if necessary, after the housing 12 has been fixed in place.

The actuating arm 13 generally resembles an elongated Y in overall configuration, having a stem or tail piece 68 from which an opposed pair of arms 69 extend. The end of the actuator shaft 16 that protrudes downwardly from the housing 12 is formed with an opposite pair of vertically disposed flats 70, parallel to the cam axis of symmetry 4-6, and which are clamped between a pair of jaws 71 provided in the free ends of the arms 69. Intermediate the jaws 71 and the tail piece 68 of the actuating arm, a slot 72 is provided for the reception of a T-block 73, which receives a machine screw 74 to clamp the actuating arm to the web of the top rail 14 of the door. In the end of the tail piece 68, a transversely disposed bolt 75 is threadedly mounted, by means of which the actuating arm 13 is adjusted laterally relative to the door 15. Obviously, when the door 15 is mounted in operative position, the actuating shaft 16 must be securely held by the actuating arm and the actuating arm, in turn, must be securely mounted in the top rail 14 of the door. But, the necessity for adjusting the door into perfect registration with its frame opening presents a difficult installation problem, particularly when it is borne in mind that the springs 33 in the housing 12 strongly bias the actuator shaft flats into the position shown in FIGURE 1, so that considerable leverage must be used to turn the shaft to an open position which would give more convenient access to the open channel of the top rail 14 of the door. Even if this difiiculty is ignored, there still remains the problem of securing the actuator shaft 70 in the jaws 71 after the actuator arm 13 has been mounted in the top rail 14. However, these and similar installation problems have been overcome by the actuator arm of my invention, which results in a door closer assembly that is concealed from view when in operative position.

Before the door 15 is mounted in its opening, the actuator arm 13 is placed within the channel of the top rail 14 and the screw 74 advanced into a tapped hole 76 formed in the web of the rail 14 along the longitudinal center line thereof and spaced from the desired position of the actuator arm 16 a distance approximately the length of the elongated slot 72. The screw 74 is fastened only sufiiciently to lightly clamp the arm 13 beneath the T-block 73, so as to permit longitudinal movement of the arm within the rail 14. It will be observed from FIGURE 7 that the arm 13 has a width less than the space between the opposed side walls of the top rail 14 and the T-block has a body portion 77 which is less than the width of the elongated slot 72. Accordingly, the actuator arm 13 can be shifted laterally relative to the top rail. The bolt on its end mounts a nut 78 over a look nut 79. The nut 78 is run onto the bolt 75 so that the overall length of the bolt and the nut is snugly but slidably receivable within the channel of the top rail 14, after which the lock nut 79 is backed up onto the nut 78 to hold this adjusted position. Thereafter, a head 39 of the bolt 75 is turned in an appropriate direction to initially dispose the longitudinal axis of the actuator arm 13 along the longitudinal center-line of the top rail 14.

As is shown in FIGURES 1 and 7, a notch 81 is formed in one of the side walls of the top rail 14, in a position to permit passage of the protruding end of the actuator shaft 16 into the channel of the top rail, by movement of the door laterally into its frame opening. As is shown in FIGURE 7, a pair of Allen head screws 82 and 83, or the like, are provided in the actuator arm 13 of the area of the jaws 71. Before the door 15 is set in its opening, the screw 83 is removed and the arm 13 is slid to the right, as viewed in FIGURE 7, within the channel of top rail 14, until the left hand end 84 of the elongated slot 72 butts against the confronting end of the T-blockv 73. The jaw end of the actuator arm 13 will then beout of the way of the notch 81 in the side wall of the top rail 14 so that the door can be placed in its frame opening to receive the actuator shaft 16 in the position indicated in FIGURE 7. Thereafter, the actuator arm 13 can be slid back to the left, as viewed in FIGURE 7, by pulling on the jaw end thereof, the bore for the bolt 83 providing a convenient purchase for this purpose. The jaws 71 of the actuator arm 13 then receive the flats 70 of the. actuator shaft 16, after which the screw 83 is reinserted, along with a spacer 85, that is positioned between the jaws 71. As both screws 32 and 83' are now accessible through the notch 81, both can be tightened to clamp the protruding end of the actuator shaft 16 in the jaws 71. As is apparent, the spacer 85 has an appropriate outer diameter for preventing shifting of the actuator arm 13 longitudinally, the actuator shaft thus being securely clamped against the bottom of the jaws.

As the actuator cam is now clamped to the actuator shaft 16, sufficient leverage can now be obtained to swing the door 15 out of the frame opening, against the force of the springs 33, and access can be had to the T-block screw 74 and the bolt 75 for adjusting the door into perfect registration with the frame opening. Thus, if it is found when the actuator shaft 16 is in the door closed position that the door 15 is then slightly angularly disposed relative to the plane of its frame opening, the bolt 75 is turned in an appropriate direction by applying a wrench to the bolt head 8i), whereby the door 15 is shifted relative to the actuating arm 13 and accordingly shifted relative to the plane of the door frame opening.

Referring to FIGURE 7, the elongated slot 72 of the actuator arm 13, toward the end having the tail piece 68, has a wider portion 86 to admit a wrench head for turning a bolt 87 that is engaged in a tapped, blind bore 88 opening into the corresponding end of the T-block 73. The head of the bolt 87 abuts the corresponding end 59 of the elongated slot 72. As the weight of the door 15 is supported on the floor hinge, and as the center of gravity of the door is offset from the hinge axis, it will be seen that, at the top of the door, the end 89 of the elongated slot 72 provides an abutment having a relatively fixed position against which a portion of the door weight is supported through the medium of the bolt 87, T-block 73 and machine screw 74. This can best be seen in FIGURE 2. As will be apparent, rotation of the bolt 87 effects an adjustment in the spacing between the machine screw 74 and the fixed abutment or slot end 89 and such adjustment, in turn, effects a raising or lowering of the swinging edge of the door to a suflicient degree to move the door 15 into registration with its frame opening. After all adjustments have been made, tht machine screw 74 is finally tightened.

While I have above disclosed but a limited number of embodiments of my invention, it is possible to produce still other embodiments without departing from the inv a h ventive' concepts herein disclosed and 1t is desired, there- E5 fore, that only such limitations be imposed on the appended claims as are stated therein or required by the prior art.

I claim:

1. In a door closer, a fluid sealed housing having reciprocable fluid displacement means mounted therein, spring means in said housing for biasing said fluid displacement means in one direction toward one end of said housing, an actuating shaft rotatably mounted adjacentthe other end of said housing and rotatable between open and closed positions corresponding to substantially open and closed positions, respective, of a door, said shaft having a cross head member carrying a pair of cam followers adjacent opposite ends thereof, a member rigidly connected to said fluid displacement means to be reciprocable therewith, said member having a curved cam portion surrounding said shaft and symmetrical about an intersecting the axis of said shaft and positioned in a plane parallel to the axis of reciprocation of said fluid displacement means, said curved cam portion being formed so as to maintain guiding contact simultaneously with both of said cam followers throughout at least a substantial portion of such rotation of said shaft between said open and closed positions and thereby positively couple the rotational movement of said shaft in either direction to the reciprocative movement of said displacement means respectively in either direction, without substantial lost motion between such reciprocative movement of said displacement means and rotational movement of said shaft in either direction over said portion of said rotation thereof.

2. In a door closer, an elongated housing having reciprocable fluid displacement means at one end, a yoke affixed to said displacement means to reciprocate with said means, an actuator shaft rotatably mounted adjacent the other end of said housing for rotational movement through a range corresponding to open and closed door positions, and having an axis of rotation normal to the plane of said yoke, a cross head integral with said shaft and carrying a pair of cam followers on opposite ends of said cross head equidistantly spaced from said axis of said shaft and disposed in the plane of said yoke, said yoke having a cam edge portion formed therein'extending in said plane around said shaft and cam followers, and having an axis of symmetry normal to and intersecting said axis of said shaft, said axis of symmetry being coincident with the plane of reciprocation of said yoke, spring means in said housing to bias said fluid displacement means toward said one end of said housing, said cam edge portion being formed so as to maintain contact'thereof simultaneously with both of said cam followers over at least a substantial portion of the range of the rotational movement of said shaft, said contact being such as positively to couple the rotational movement of said shaft to the reciprocative movement of said yoke, such that the reciprocative movement of said yoke and displacement means in both directions positively follows the respective rotational movement of said shaft in both directions, without substantial lo'st motion therebetween over said portion of saidrange of rotational movement.

References Cited in the tile of this patent UNITED STATES PATENTS 1,120,544 Rosentreter Dec. 8, 1914 1,147,909 Williams July 27,, 1915 2,585,625 Carlson Feb. 12, 1952 2,586,135 Woodrulf Feb. 19, 1952 2,603,818 Carlson July 22, 1952 2,972,788 Shean Feb. 28, 1961 

1. IN A DOOR CLOSER, A FLUID SEALED HOUSING HAVING RECIPROCABLE FLUID DISPLACEMENT MEANS MOUNTED THEREIN, SPRING MEANS IN SAID HOUSING FOR BIASING SAID FLUID DISPLACEMENT MEANS IN ONE DIRECTION TOWARD ONE END OF SAID HOUSING, AN ACTUATING SHAFT ROTATABLE MOUNTED ADJACENT THE OTHER END OF SAID HOUSING AND ROTATABLE BETWEEN OPEN AND CLOSED POSITIONS CORRESPONDING TO SUBSTANTIALLY OPEN AND CLOSED POSITIONS, RESPECTIVE, OF A DOOR, SAID SHAFT HAVING A CROSS HEAD MEMBER CARRYING A PAIR OF CAM FOLLOWERS ADJACENT OPPOSITE ENDS THEREOF, A MEMBER RIGIDLY CONNECTED TO SAID FLUID DISPLACEMENT MEANS TO BE RECIPROCABLE THEREWITH, SAID MEMBER HAVING A CURVED CAM PORTION SURROUNDING SAID SHAFT AND SYMMETRICAL ABOUT AN AXIS INTERSECTING THE AXIS OF RECIPROCATION OF SAID FLUID A PLANE PARALLEL TO THE AXIS OF RECIPROCATION OF SAID FLUID DISPLACEMENT MEANS, SAID CURVED CAM PORTION BEING FORMED SO AS TO MAINTAIN GUIDING CONTACT SIMULTANEOUSLY WITH BOTH OF SAID CAM FOLLOWERS THROUGHOUT AT LEAST A SUBSTANTIAL PORTION OF SUCH ROTATION OF SAID SHAFT BETWEEN SAID OPEN AND CLOSED POSITIONS AND THEREBY POSITIVELY COUPLE THE ROTATIONAL MOVEMENT OF SAID SHAFT IN EITHER DIRECTION TO THE RECIPROCATIVE MOVEMENT OF SAID DISPLACEMENT MEANS RESPECTIVELY IN EITHER DIRECTION, WITHOUT SUBSTANTIAL LOST MOTION BETWEEN SUCH RECIPROCATIVE MOVEMENT OF SAID DISPLACEMENT MEANS AND ROTATIONAL MOVEMENT OF SAID SHAFT IN EITHER DIRECTION OVER SAID PORTION OF SAID ROTATION THEREOF. 